


Goo Monsters Don't Wear Red Gym Shorts

by beanmom



Series: Teacher AU [6]
Category: Promare (2019)
Genre: Alternate Universe - Creatures & Monsters, Alternate Universe - Student/Teacher, Dubious Consent, M/M, Masturbation, Murder, Power Imbalance, Slime, Tentacle Monsters, Tentacle Sex, when i say graphic depictions of violence i mean graphic depictions of violence ok
Language: English
Status: Completed
Published: 2020-01-14
Updated: 2020-01-14
Packaged: 2021-02-27 09:55:29
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 2,308
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22245205
Author URL: https://archiveofourown.org/users/beanmom/pseuds/beanmom
Summary: The new gym teacher at Promepolis High might not be entirely human. He might not even be entirelysolid. Sometimes he acts strangely. Too strange. Lio is absolutelyfascinatedby him.AKA: What if goolo started posing as a teacher to get easy access to students to eat(yes it's a goolo/teacher au crossover)
Relationships: Lio Fotia/Galo Thymos
Series: Teacher AU [6]
Series URL: https://archiveofourown.org/series/1594783
Comments: 22
Kudos: 93





	Goo Monsters Don't Wear Red Gym Shorts

**Author's Note:**

> I'm not affiliated with the creator of goo galo/goolo au in any way and I wrote this for fun bc I love monsters so do us both a favor and hit the back button if ur not prepared to look at the content I've specified in the tags. 
> 
> What can I say i saw a goo creature and wanted him to be a monster 
> 
> Now that being said if ur still here? Hope u enjoy!!

The new gym teacher at Promepolis High is... _strange_. Lio's never seen him eat, not once in the whole time he's been there. Sure, he's a brand new teacher, Lio hasn't spent that much time with him, but he's gotta eat sometime, right? All he's ever seen is Mr. Thymos drinking water. Almost excessive amounts of water. He could excuse as the fact that the teacher exercises all the damn time, even running alongside the students, replenishing his fluids, if not for... the _other_ strange things.

Sometimes, out of the corner of Lio's eye, he would swear that he saw something amorphous, some kind of blue blob, but every time he turns to get a closer look, all he sees is the gym teacher standing right there next to him, with a smile on his face. He's friendly with the students. _Too_ friendly. Not in the way that would make Lio think he's a creep, but in the way that every student trusted him, in the easygoing way that some teachers make friends with their students. Something about him sends a shiver down Lio's spine. But at the same time, Lio _wants_ him. There's something appealing about his mystery, about his genuine openness, and Lio wants to break him open and find out what secrets he's been hiding. 

Lio watches him. Keeps an eye on him for weeks, but Mr. Thymos never slips up. He never _eats._ When Lio does catch him around, he's always got an easygoing smile on his face, a casual demeanor. When Lio talks to him, he's more than amicable, but the gym teacher is less of a pushover than he comes off as. When he corners Mr. Thymos in the locker room, ready to push him down and force him to Lio's will, he doesn't look the least bit scared. 

His eyes flash dangerously before settling back on their usual easygoing demeanor. Lio thought he'd be the type who wouldn't fight back. But that look in his eyes... he most certainly is. Mr. Thymos feels like an animal, like some kind of _creature_. 

It's certainly an unsettling vibe to get from someone who's supposed to be your gym teacher. But at the same time, it's _appealing_. Lio keeps following him. He's gotta slip up someday. One day. 

That's how he finds himself behind the school, hiding behind a dumpster, keeping an eye on him. It looks like he's talking to a student. Lio keeps careful watch, eyes narrowing. He's too far away to hear the conversation, but he has a good view of both of their faces. Lio recognizes the student. Often in trouble, often picks on the smaller kids, the kids who are visibly different. More likely than not, he was in trouble again, and Mr. Thymos was giving him a stern talking to. Lio peers closer. 

Mr. Thymos puts a hand on the student's shoulder. If Lio had blinked, he would've missed it. His hand goes _liquid_. The blue, gooey amorphous blob he's been seeing out of the corners of his eyes. The student nearly cries out, but Mr. Thymos' other hand slaps over his mouth, going just as gooey and liquid as the first. His body bubbles, flesh melting into unnatural blue goo. 

Fuck. Lio's cock is hard. Mr. Thymos' face opens, like a snake's, twisting unnaturally until the student becomes completely encased in his gooey body. Slowly, the goo contracts, _quivering_ , and Lio can see the student inside of him, eyes wide, mouth open in a silent scream. He's still _alive_ , writhing and twisting inside the viscous goo, god, no matter how good of a swimmer the kid might've been is no match for the thickness of the fluid.

And Lio understands now, why Mr. Thymos always wore those tiny little red gym shorts and no shirt. When you're made of goo, it must be so hard not to melt your own clothes. Lio slips a hand into his pants, biting his hand to keep himself quiet. 

Half of Mr. Thymos' body is still gooey, thick blue fluid with the slowly melting child inside of him. It's like a melting flesh peach, with the flesh becoming visibly softer over time. It's a slow process but Lio can imagine how it would go, over time the hair and nails being the first to melt away, flesh pulling away from the bone. It's the same way the white sticks to the shell of a hard boiled egg, but ultimately comes away clean. Lio can't take his eyes off of him. It's beautiful, in the same way that watching a lion tear out a zebra's throat is beautiful. Beautiful in the pure feral _nature_ of it, although the type of creature he's looking at is certainly unnatural.

The idea of Mr. Thymos' flesh melting into goo underneath him makes him hot, his cheeks burning. He bites hard on his hand as he squeezes himself, and he releases into his hand with a soft groan. Mr. Thymos' head whips around, an unnatural 180 degrees. His neck is blue, gooey veins dripping down his bare back. Lio's heart seizes, and he wipes his hand on the grass behind the dumpster, quickly ducking out of sight. He waits, far longer than he thinks is necessary and peeks around the edge of the dumpster. 

Mr. Thymos is standing in front of him, looking down with a big grin on his face. "Lio!" He says, cheerfully, "What are you doing down there?" He extends a hand, and Lio thanks his lucky stars he wiped his off before grabbing Mr. Thymos' and letting him help Lio stand up.

Lio laughs. He's always been good at covering up how he really feels. And although he's screaming inside, his voice is steady when he goes "Oh, I was just waiting to be picked up, you caught me in the middle of a fall!" 

Looking into Mr. Thymos' eyes, he can tell the so-called gym teacher doesn't believe him. But then again, it's not like anyone would believe him either. Does he know what Lio saw? It's very likely. So why didn't he just eat Lio as well? 

There's a string of missing persons cases recently. If this were the 1980s, there would be a plethora of faces on milk cartons, missing students from his very school. The parents start to keep a more watchful eye on their kids, and there's an escort for kids who walk to school. No one has any reason to suspect that Galo Thymos, nonchalant, amiable, Galo Thymos, had anything to do with it.

Lio doesn't know why Mr. Thymos didn't eat him right there and then. But he didn't _care_ , surprisingly, more cavalier with his own safety than he normally would be, with the obsession he has over the gym teacher. His stalking is more furious, more deranged. He tracks Mr. Thymos' location at all times. He's even got a record of his feeding schedule, how much water he drinks in a day. He wonders, sometimes, if Mr. Thymos knows how much Lio's been following him. He pushes the thought out of his mind. 

He eats once a month. Sometimes it's a misbehaving student, or a prejudiced faculty member. More often, it's some poor homeless person. Someone who society wouldn't miss. And with the whole body being digested, there was no chance of finding him. It still made Lio's cheeks hot and his cock wet to watch Mr. Thymos feed. He almost wishes Mr. Thymos would be translucent more often so he could watch the victims melt all the way. He wants to know what the flesh looks like when it's in a half melted state. But, whenever he saw Mr. Thymos feed, there was just a trace of the previous skeleton left behind. 

It was nearly half a year before he approached Mr. Thymos again. He'd done research. He carried a lighter. He was going to _own_ that gooey monster if it was the last thing he did. And the next time he cornered Mr. Thymos in the locker room, he pushed him against the wall, pressed a knee between his legs. 

Mr. Thymos _laughs_ at him. "Oh, I could just eat you up," he says. He'd be insulted normally, that someone thought he was _cute_ , but the delivery comes off differently here. It's a threat. 

Lio meets his gaze. "You're a three course meal, Mr. Thymos." Lio lowers the lighter. Mr. Thymos lets out a bloodcurdling screech, flesh bubbling into blue ooze wherever the fire touched him.

"I was going to let you live, you know." Mr. Thymos snarles at him, his abdomen melting into blue goo. Lio could see the half digested skeleton of his previous victim floating inside. Lio had watched him eat her, and now she was hardly recognizable. Chunks of flesh still clung to the bone. Gooey tentacles form from his stomach, wrapping around Lio's waist. "I found you _endearing_. And you _touched_ yourself to the sight of me, the _real_ me." 

Lio struggles, twisting the lighter in his hand. His hands are still mostly free, and he runs the flame over the tentacles, another inhuman screech coming from Mr. Thymos' throat. If it was a throat. Lio's cock is hard. His cheeks burn with angry arousal as his hands claw into Mr. Thymos' chest, tearing out chunks of gooey flesh. They're lucky that no one's here after school because Mr. Thymos is _loud_. Tentacles wrap around his wrists with sharp points, the ones around his waist spiking into him like knives. They're pulled away as Lio falls to his knees, soaked in blood and goo. 

"Don't make me eat you." Mr. Thymos says, almost sadly. "It'll be so _boring_ without you." 

Lio doesn't answer, just snarls like an animal. Goo and blood drip down his stomach, his shirt punctured through and ruined, melting from the goo's acidity. He clutches his stomach and looks up at the monster in front of him. "I'm going to _own_ you." 

He lunges, lighter in hand, ripping fist fulls of burnt goo out of Mr. Thymos' body, melting away whatever he can with the lighter. His pants are corroded, and his skin aches, but he can't bring himself to care. He manages to knock Mr. Thymos to the ground, taking him by surprise before he can shift completely into goo. 

Lio's straddling him, as much as he can. Mr. Thymos' body is a shiny blue goo, the gym shorts melting away as fast as Lio's own clothes. He's still shaped like a human being, still got the same face and hair and eyes, but it's all dripping, all melting, and Lio sits on his gooey chest, hard cock pressed between Mr. Thymos' pecs. It's slimy, but there's some solidness to him, and Lio wonders for a second how much of that is because Mr. Thymos _wants_ this. 

"Oh, is _that_ what you wanted?" The goo monster laughs. "I can't say I blame you. I'm sure you're wondering what it feels like."

Lio's lip curls. "Shut the fuck up." 

"Make me." Gooey tentacles wrap around his waist. 

"God, you're insufferable," Lio snaps, and shoves his cock right into Mr. Thymos' stomach. The gooey flesh parts so _easily._ It's nothing like fucking a human being, it's not _tight_ , and he can see his cock inside him, but it's unexpectedly warm and hot, and Lio rocks his hips back and forth and _moans_. Is this really what he'd been dreaming about for months? He can see the little drops of precum floating away inside Mr. Thymos' body and he moans loudly, fucking harder and harder. 

Gooey tentacles wrap around his bare waist, sliding between his legs. Lio groans as the tentacle breaches him, and it's just as hot and slimy as the inside of Mr. Thymos' abdominal cavity, but somehow having it inside him makes it so much _wetter._ He thrusts his hips hard into that wet heat, and Mr. Thymos just _grins_ underneath him. Lio hates it. He hates that every stroke is pulling him apart, every thrust of the tentacle inside of him making him see stars, but he can't do a _thing_ to break this monster underneath him. The lighter is too far away. And frankly, he's enjoying himself too much.

Tentacles snake up his chest, rubbing his nipples, and Lio gasps, his hands squeezing Mr. Thymos' shoulders so hard they slip inside him, and he's got no leverage, desperately thrusting his hips, still bleeding, still covered in goo. 

Some of his blood slips inside Mr. Thymos' body, and the goo monster shudders, amorphous flesh convulsing. "It's so _hard_ not to eat you," Mr. Thymos groans. "The blood is the best part. Usually I have to _wait_."

Lio doesn't know why, but that just makes the arousal curling in his abdomen stronger, and his hips start to go erratic after a short while, the combination of the warm wetness surrounding his cock and the tentacle massaging his prostate makes him _wail._ He cries out, and fuck, the sight of his own cum filling up Mr. Thymos' body, watching his own orgasm is almost enough to make him hard again. Almost.

His cum floats around inside Mr. Thymos' body and Lio stares at him, looking at the way he shudders. " _Oh_ ," Mr. Thymos gasps. "That's... that's even better than the blood." 

The tentacles inside him retract back into Mr. Thymos' body. If either of them are boneless, of course, it's Mr. Thymos, but Lio is _exhausted_ , and he falls, limp, onto Mr. Thymos' chest. The body underneath him solidifes, until he's looking at his usual gym teacher. The goo and bloodstains everywhere look almost out of place.

"I'm going to own you, Mr. Thymos." Lio says, repeating his statement from earlier. 

"I'd like to see you try." Mr. Thymos replies. "And call me Galo." 

**Author's Note:**

> Man imagine them working together wouldn't that be wild 
> 
> Thanks for reading come yell at me [@whoredeity](https://twitter.com/whoredeity) on twitter!!
> 
> THERE'S [FANART](https://twitter.com/uedasen_pr/status/1218166170466938881?s=19) OF THIS FIC NOW IM LOSING MY MIND IM SO FLATTERED


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